Colin Callender, president of HBO Films, is leaving the network to start his own entertainment company, HBO announced on Tuesday.

Callender's departure will bifurcate HBO Films into miniseries and movies divisions. Kary Antholis will become president, HBO Miniseries and Len Amato will become president, HBO Films. Both will report to Michael Lombardo, president, Programming Group and West Coast Operations.

Callender has been at HBO since 1987. During his tenure, he has stewarded a roster of critically hailed and award-winning projects including Miss Evers' Boys, The Gathering Storm, Gus van Sant's Elephant and Mike Nichols' Angels in America.

HBO as usual dominated the movie and miniseries categories at this year's Emmy awards, winning a record-breaking 13 Emmys for John Adams (including Outstanding Miniseries) and three for Recount (including Outstanding Made for Television Movie).

"This past year at HBO Films has been nothing less than extraordinary, and it's the perfect time for me to move on to a new challenge," said Callender in a statement. "My career has been shaped by the one constant in this industry - change - and for some time I've had a hankering to return to my entrepreneurial roots. With the industry in the midst of a major transformation, and coming off this great year, I can't think of a better time to launch my own company."

Details of Callender's new venture will be announced early next year.

Callender, who is British, came to HBO after a career in the U.K. where he ran his own production company, The Callender Company Ltd. As he returns to independent production, he's likely to maintain a close relationship with HBO.

"Colin's contributions over these many years have been nothing short of extraordinary," said Richard Plepler, co-president, HBO, in a statement. "His vision, intelligence and unique talent are responsible for the widespread acclaim his films and miniseries receive year after year. We will certainly miss him and hope and expect to have a continued collaboration with Colin and his new company."